tube rectifier life expectancy

[Raj1]

Hi,

My AZ1 rectifier seems to have failed. I a little suprised as it was being run at specified parameters. I've only been using this tube for about a year, and even then, the cd player was not on all the time.....

I've checked connections to the heater supply and these seem fine, the filaments however won't heat up, so I assume that it's done...
So have I just been unlucky, or should it have lasted longer....

thanks
Raja

 

[Jax]

Pull the tube and measure the filament resistance, it should be very low if the filament is OK.

Did you run the filament at 4V?

 

[Raj1]

Hi,


Thanks for the reply,
Yes the filament was run at 4v, I'll check the resistance asap.


Cheers
Raja

 

[analog_sa]

How big is your first cap? I would expect these old frail rectifiers to last longer with choke input supplies.

 

[Raj1]

Hi,


the scehmatic can be found here
http://www.ultranalog.com/cdenhancer/cdenhancer2_3a5.pdf

perhaps the rectifier was too old and too frail, I bought it unused, so I did expect it to last at least a few years.......


Thanks
Raja

 

[Jax]

AZ1 is a rugged rectifier with max 60uF at 2x300V and 2x60 ohms.

It should have lasted a lifetime in that circuit. My guess is a "monday" specimen of the tube with either a poor weld or poor vacuum.

Check the solderings on its pins, could be an intermittent contact. The socket could also be a problem.

 

[Raj1]

It should have lasted a lifetime in that circuit. My guess is a "monday" specimen of the tube with either a poor weld or poor vacuum.

Hi,

Your guess is correct, there is no vacuum, the base for the tube has rusted, there is at least one hole, clearly visible to the eye. I won't be buying another from this particular supplier.

Thanks
Raja

 

[analog_sa]

Looking at the circuit i can only agree with Jax - it should last a long time.

Btw Raja, nice circuit. How do you like it?

 

[Raj1]

Hi,

The circuit is very very good, best cd sound I've heard, I run mine without the rolloff caps or input resistors....

In a way having this up and running has kept me away from vinyl, I am looking at getting a turntable, but I question whether it'll sound any better unless I spend some serious cash. Turntable wise I've looked at the garrard 301/401 or linn lp12. Both seem to pop up every now and again, but are also steeped in controversy.......

Can you reccommend any good phono stage circuits, looking for a minimalistic approach.........


Thanks
Raja

 

[RetroAudio]

Raj1 - a side note here, why is C10 in parallel with R11 in your LM317 regulator circuit? Just curious.

 

[Raj1]

Hi,

it may appear confusing, but the cap is between the adjust and output pins, afaik this help to quiten noise on the output of the regulator......

thanks
Raja

 

[RetroAudio]

did you actually hook up a scope probe to see that this worked the way you thought, both with and without cap? Just curious again.

 

[Raj1]

Hi,

I didn't actually design the circuit, for that we can credit occasional user ultranalog, if it's specs and noise figures you're interested in, there was a whole series of information presented on tnt audio a few months ago, using the cap between these pins helps to reduce noise, do a search on the website of tnt, sift thru the article, this should give you the info you desire...........

Thanks
Raja